A polyimide resin that exhibits excellent heat resistance, electrical properties, mechanical properties, and the like has been used as a surface protective film, an interlayer dielectric, and the like for semiconductor devices. In recent years, a polybenzoxazole resin that exhibits excellent moisture resistance due to the absence of a carbonyl group derived from a polar imide ring, has been used. By adding the photosensitivity to rein, the photosensitive resin composition that can reduce the patterning process has been developed.
A positive-type photosensitive resin composition developable with an alkaline aqueous solution, that includes a polybenzoxazole precursor and a diazoquinone compound (photosensitizer), has been developed in order to improve safety (see Patent Document 1).
A relief pattern is formed as follows using a positive-type photosensitive resin composition. Note that the following focuses on the development mechanism. Actinic rays are applied to a film formed on a wafer through a mask using a stepper so that an exposed area and an unexposed area are obtained. The diazoquinone compound included in the unexposed area is insoluble in an alkaline aqueous solution, and is provided with resistance to an alkaline aqueous solution as a result of interaction with a resin. The diazoquinone compound included in the exposed area chemically changes due to the actinic rays, and becomes soluble in an alkaline aqueous solution, so that dissolution of the resin is promoted. A relief pattern can be formed by dissolving (removing) the exposed area by utilizing a difference in solubility between the exposed area and the unexposed area.
In recent years, high-performance semiconductor devices have been rapidly developed, and a semiconductor device that implements an increase in speed and a reduction in size, cost, and power consumption has been desired. Therefore, it is necessary to reduce the size of the semiconductor element of the semiconductor device, and the relief pattern of the element has been reduced in size. As a result, the contact area of a film and a substrate has decreased. When using the photosensitive resin composition disclosed in Patent Document 1, a fine relief pattern may be removed from a substrate during development, or a cured film may be removed after humidification. (Patent Document 1) JP-B-1-46862